gdbsupport/environ.cc

   1 /* environ.c -- library for manipulating environments for GNU.
   2
   3    Copyright (C) 1986-2024 Free Software Foundation, Inc.
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include "environ.h"
  19 #include <algorithm>
  20 #include <utility>
  21
  22 /* See gdbsupport/environ.h.  */
  23
  24 gdb_environ &
  25 gdb_environ::operator= (gdb_environ &&e)
  26 {
  27   /* Are we self-moving?  */
  28   if (&e == this)
  29     return *this;
  30
  31   this->clear ();
  32
  33   m_environ_vector = std::move (e.m_environ_vector);
  34   m_user_set_env = std::move (e.m_user_set_env);
  35   m_user_unset_env = std::move (e.m_user_unset_env);
  36   e.m_environ_vector.clear ();
  37   e.m_environ_vector.push_back (NULL);
  38   e.m_user_set_env.clear ();
  39   e.m_user_unset_env.clear ();
  40   return *this;
  41 }
  42
  43 /* See gdbsupport/environ.h.  */
  44
  45 gdb_environ gdb_environ::from_host_environ ()
  46 {
  47   extern char **environ;
  48   gdb_environ e;
  49
  50   if (environ == NULL)
  51     return e;
  52
  53   for (int i = 0; environ[i] != NULL; ++i)
  54     {
  55       /* Make sure we add the element before the last (NULL).  */
  56       e.m_environ_vector.insert (e.m_environ_vector.end () - 1,
  57                                  xstrdup (environ[i]));
  58     }
  59
  60   return e;
  61 }
  62
  63 /* See gdbsupport/environ.h.  */
  64
  65 void
  66 gdb_environ::clear ()
  67 {
  68   for (char *v : m_environ_vector)
  69     xfree (v);
  70   m_environ_vector.clear ();
  71   /* Always add the NULL element.  */
  72   m_environ_vector.push_back (NULL);
  73   m_user_set_env.clear ();
  74   m_user_unset_env.clear ();
  75 }
  76
  77 /* Helper function to check if STRING contains an environment variable
  78    assignment of VAR, i.e., if STRING starts with 'VAR='.  Return true
  79    if it contains, false otherwise.  */
  80
  81 static bool
  82 match_var_in_string (const char *string, const char *var, size_t var_len)
  83 {
  84   if (strncmp (string, var, var_len) == 0 && string[var_len] == '=')
  85     return true;
  86
  87   return false;
  88 }
  89
  90 /* See gdbsupport/environ.h.  */
  91
  92 const char *
  93 gdb_environ::get (const char *var) const
  94 {
  95   size_t len = strlen (var);
  96
  97   for (char *el : m_environ_vector)
  98     if (el != NULL && match_var_in_string (el, var, len))
  99       return &el[len + 1];
 100
 101   return NULL;
 102 }
 103
 104 /* See gdbsupport/environ.h.  */
 105
 106 void
 107 gdb_environ::set (const char *var, const char *value)
 108 {
 109   char *fullvar = concat (var, "=", value, (char *) NULL);
 110
 111   /* We have to unset the variable in the vector if it exists.  */
 112   unset (var, false);
 113
 114   /* Insert the element before the last one, which is always NULL.  */
 115   m_environ_vector.insert (m_environ_vector.end () - 1, fullvar);
 116
 117   /* Mark this environment variable as having been set by the user.
 118      This will be useful when we deal with setting environment
 119      variables on the remote target.  */
 120   m_user_set_env.insert (std::string (fullvar));
 121
 122   /* If this environment variable is marked as unset by the user, then
 123      remove it from the list, because now the user wants to set
 124      it.  */
 125   m_user_unset_env.erase (std::string (var));
 126 }
 127
 128 /* See gdbsupport/environ.h.  */
 129
 130 void
 131 gdb_environ::unset (const char *var, bool update_unset_list)
 132 {
 133   size_t len = strlen (var);
 134   std::vector<char *>::iterator it_env;
 135
 136   /* We iterate until '.end () - 1' because the last element is
 137      always NULL.  */
 138   for (it_env = m_environ_vector.begin ();
 139        it_env != m_environ_vector.end () - 1;
 140        ++it_env)
 141     if (match_var_in_string (*it_env, var, len))
 142       break;
 143
 144   if (it_env != m_environ_vector.end () - 1)
 145     {
 146       m_user_set_env.erase (std::string (*it_env));
 147       xfree (*it_env);
 148
 149       m_environ_vector.erase (it_env);
 150     }
 151
 152   if (update_unset_list)
 153     m_user_unset_env.insert (std::string (var));
 154 }
 155
 156 /* See gdbsupport/environ.h.  */
 157
 158 void
 159 gdb_environ::unset (const char *var)
 160 {
 161   unset (var, true);
 162 }
 163
 164 /* See gdbsupport/environ.h.  */
 165
 166 char **
 167 gdb_environ::envp () const
 168 {
 169   return const_cast<char **> (&m_environ_vector[0]);
 170 }
 171
 172 /* See gdbsupport/environ.h.  */
 173
 174 const std::set<std::string> &
 175 gdb_environ::user_set_env () const
 176 {
 177   return m_user_set_env;
 178 }
 179
 180 const std::set<std::string> &
 181 gdb_environ::user_unset_env () const
 182 {
 183   return m_user_unset_env;
 184 }